Electronic part and electronic control unit

Abstract

A main body of an electronic part is formed in a rectangular pillared shape having a first and a second axial end surface. A first electrode is formed on the first axial end surface electrically and mechanically connected to a first wiring pattern formed on a board surface of a printed board. A second electrode is formed on the second axial end surface, to which one end of a fuse terminal is electrically connected. The other end of the fuse terminal is connected to a second wiring pattern of the printed board or a wiring member which is formed as an independent member from the printed board. A cut-off portion is formed in a connecting portion of the fuse terminal.

What is claimed is: 
     
       1. An electronic part mounted to a printed board comprising:
 a main body of a pillared shape, the main body having at least one electronic element; 
 multiple electrodes respectively formed at outer surfaces of the main body, each of the electrodes being electrically connected to the electronic element; and 
 at least one fuse terminal electrically connected to one of the electrodes, 
 wherein the electrodes are composed of a first electrode formed at a first axial end surface of the main body and a second electrode formed at a second axial end surface of the main body, the first and second axial end surfaces are opposing to each other in an axial direction of the main body, 
 wherein the main body is arranged on the printed board in such a way that the first axial end surface is opposed to a board surface of the printed board, 
 wherein the first electrode is electrically connected to a first wiring pattern formed in the printed board, 
 wherein the second electrode is electrically connected to a second wiring portion via the fuse terminal, 
 wherein the fuse terminal is composed of; 
 an electrode-connected portion electrically and mechanically connected to the second electrode; 
 a wire-connected portion electrically and mechanically connected to the second wiring portion; and 
 a connecting portion extending from the electrode-connected portion in a direction away from the main body and further extending in the axial direction of the main body in order to electrically connect the electrode-connected portion to the wire-connected portion, 
 wherein the connecting portion has a cut-off portion, which has a cross sectional area smaller than that of other portions of the fuse terminal and which is melted down by heat generated by excess current flowing through the cut-off portion. 
 
     
     
       2. The electronic part according to  claim 1 , wherein
 the electrode-connected portion of the fuse terminal is connected to the second electrode formed on the second axial end surface of the main body. 
 
     
     
       3. The electronic part according to  claim 2 , wherein
 the fuse terminal has a flat plate portion, in which the electrode-connected portion is formed, 
 an upper-side surface of the flat plate portion is perpendicular to the axial direction of the main body. 
 
     
     
       4. The electronic part according to  claim 1 , wherein
 the fuse terminal has an arm portion, which extends from the fuse terminal in a direction perpendicular to the axial direction of the main body toward the main body, and 
 a forward end of the arm portion is in contact with a side surface of the main body, in which the first and second electrodes are not formed. 
 
     
     
       5. The electronic part according to  claim 4 , wherein
 the cut-off portion is formed in the connecting portion between the electrode-connected portion and the arm portion. 
 
     
     
       6. The electronic part according to  claim 5 , wherein
 the main body is formed in a rectangular pillared shape and has four side surfaces, 
 the fuse terminal has a pair of arm portions, each of which is respectively in contact with the side surfaces of the main body, wherein the side surfaces are opposed to each other. 
 
     
     
       7. The electronic part according to  claim 1 , wherein
 a width of the cut-off portion is smaller than that of other portions of the fuse terminal, wherein the width corresponds to a dimension in a direction perpendicular to a thickness direction of the cut-off portion. 
 
     
     
       8. The electronic part according to  claim 1 , wherein
 the second wiring portion is composed of a wiring pattern formed on a board surface of the printed board. 
 
     
     
       9. The electronic part according to  claim 1 , wherein
 the second wiring portion is composed of an independent wiring member separately formed from the printed board. 
 
     
     
       10. An electronic control unit comprising:
 the electronic part according to  claim 8 ; and 
 the printed board having a first wiring pattern and a second wiring pattern, wherein a first electrode of the electronic part is electrically connected to the first wiring pattern and a second electrode of the electronic part is electrically connected to the second wiring pattern. 
 
     
     
       11. An electronic control unit comprising:
 the electronic part according to  claim 9 ; 
 the printed board having the first wiring pattern, to which the first electrode of the electronic part is electrically connected; and 
 the second wiring portion, which is composed of the independent wiring member separately formed from the printed board and to which the second electrode of the electronic part is electrically connected.